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This morning I started the 54 Packard Cavalier to drive it to work and it made a trip around the block running normal and then the engine started to stumble and not rev up.

I should mention we have had heavy rain and high humidity here in Phoenix since the car was driven last weekend.

About ? a tank of gas on the gauge.

I have a free flow of gas at the electric booster pump on the frame rail from the tank and I removed the inlet screen on the carb and turned on the electric pump and gas is flowing.

When I first got this car a couple of years ago the previous owner had installed the electric pump and sometimes the engine would do a similar stumble and he turned on the pump and it smoothed out. I run with this very low pressure pump on all the time and have had no problems.

I removed the Distributer cap and left it open for a while in case of moisture but didn't see any signs. I have had spark plug wires get weird after a heavy rain in my past.

It acts starved for gas and I am wondering about a stuck float valve in the carb (Carter original 4 barrel).

If I let the pump run for a minute it will start and run briefly and then start the stalling.

I don't know if these engines can slip timing.

I am planning to put some gas straight into the top of the carb and see how it runs.

Yes I am aware of the crappiness of modern gas.

I also have a couple of crazy neighbors who are at war and wonder what sugar will do in ethanol gas, noting his car has gone off on a wrecker the past couple of days. The fuel filters do not appear clogged, noting sugar doesn't dissolve in real gas. Water can have a similar effect.

I'm considering all the possibilities.

Jim

I would like to mention a recent experience with "modern" gas, l
live in the "boonies" and keep a large generator gassed up and
ready since when we lose power we are among the last to get it back.
I usually keep the tank full, but had not filled it since the last use, about six months ago.
This week we needed it again, when I started it I got a large puff of
white smoke and it wouldn't run without the choke.
When I finally got around to checking the fuel there was a large layer
of what appeared to be water at the bottom, the ethanol had combined
with condensation as the tank"breathed".
Since you mentioned you had one half tank and had been having high
humidity I thought I would mention this since you might not usually have this problem.

This morning I started the 54 Packard Cavalier to drive it to work and it made a trip around the block running normal and then the engine started to stumble and not rev up.


Could have been accumulated water in the gas as Kansasboy suggested. The run around the block could have used up the uncontaminated gas in the fuel line, and started pulling water out of the tank.

There were three different scenarios when my cars would run OK for a mile or two from initial start, then stumble:

-automatic choke comes off too soon and mixture leans out

-carb ices up and richens mixture too much....I'll assume carb icing isn't a problem in Phoenix in September

-automatic choke sticks closed and does not come off, richening mixture too much.

If the gas isn't contaminated, my first guess would be a sticking automatic choke. When it died, did you notice if the choke was open or closed? Is there a lot of soot in the exhaust pipe?

Sticks in my mind if the mixture was too lean, the engine would rev OK in neutral, but wouldn't pull under load. If the choke was stuck closed, it wouldn't rev under any conditons because it couldn't get air.

If the engine is running too lean, it might be more prone to pinging, because combustion temps are higher. If too rich, it might backfire.

The engine in this video sounds to me like it's running too rich at idle. It stumbles and backfires. When the guys crank up the throttle they blow out the excess gas and it runs smoothly until it starts to load up again.

http://www.youtube.com/watch?v=tuMvqp7fWUU

I didn't think of carb icing but when I finally get some play time I will explore this further.

The car is driven essentially daily and Sunday 9/7 the temperature here in Phoenix was about 100. We call this fall.

We got lots of rain starting Monday morning and by Monday night 5 inches had accumulated. We only get about 7 inches in a year. My driveway in which the Packard is parked had a good inch of standing water and the humidity here is extremely high.

Automatic choke was full opened and free.

Two fuel filters and sufficient gas flow at the inlet of the carb. I removed the cap and screen.

I have never found rust or any debris in the fuel system and the screen was completely clean.

I started the engine and backed out onto the street and decided to go around the block and park in front of my house before leaving for work. It made the complete block and started the stumble as I parked. I was able to pull back into the drive but the stumble was getting worse.

I didn't see any smoke from the exhaust either black or white. I smelled for raw gas but couldn't pick up a scent.

Jim

Did you check the distributor point gap or dwell? Sometimes, the rubbing block wears out and essentially closes the points. That would give the symptoms you have described.

Craig

<i>I didn't think of carb icing but when I finally get some play time I will explore this further.</i>

The only time I had trouble with the carb icing was in the dead of a Michigan winter with temps barely above zero, and my drive to work/class was only 2 or 3 miles so the engine never really got warmed up.

Seems that if you had some sort of ignition failure, it would have happened from start, not a mile or two after start.

You eliminated the possibility of the choke being stuck closed.

I'm going to go with Kansasboy: contaminated gas. The run around the block used up the gas in the fuel line and you got down to stuff pulled from the tank. I gassed up in Auburn after visiting the ACD museum last year. About a mile later the engine started stumbling.

If you can use a glass container and pump some fuel into it, if there is a separation layer it will likely be mostly ethanol with a little water, it will burn but will not run
well, it will seem to run lean because it takes approx. 30% more volume of ethanol to run properly at a given amount of
air volume. It takes a very small amount of water to make the ethanol separate from the gasoline. But it shouldn't ice up as ethanol is a pretty good anti-freeze.If the problem is like that I had this week, it is because the engine just doesn't like to run on just ethanol.

Why not just simply drain the gas tank, flush the lines all the way thru to the inlet to the carburetor, and refill with fresh gasoline. If nothing else, you'll eliminate this as a cause. If you have no way to discard the old gas, keep it for cleaning dirty parts.

If you think you might have a stuck float, easy enough to tell. Turn on your electric pump; if it's stuck down (sunk) gas will soon overflow the carburetor bowl vent - something you can't miss. If you think it's stuck up (closed), just open the choke valve and stroke the pedal linkage and look for 2 streams of gas from the accelerator pump jets.

For a wet distributor cap and wires, a spritz with WD-40 and a wipedown works well. And don't ignore the possibility of moisture around the high tension lead at the coil - not uncommon on wet ignition systems to see blue flash from the coil centerpost to the metal shell - try starting in a dark garage and see what you see.

Owen's right of course,I wasn't suggesting trying to run on the gas if it is bad, just that is unlikely to be icing.

In the few minutes I got to work on the car last night, it appears that ignition is the likely culprit.

I expect the condenser inside the distributer has become shorted.

I have one of the old timing lights that has a neon flash tube and with it plugged into a sparkplug wire and the other side to ground there is almost no spark.

The points appear to open properly.

The car was running normal for one trip around the block and then it slowly started to fail. I managed to get it off the street and into the driveway. At this point it won't fire at all.

With the air cleaner off the accelerator pump delivers a good squirt of gas and I have already verified fuel flow to the carb.

I of course cleaned off the work bench just this past weekend and tossed out an old condenser which did work abou8t three years ago. I don't know if the local Autozonies still sell points and condensers. I'm thinking they are all about the same value which is 0.2 mFd in capacitor land. I may cut the old one loose and tag one on at the coil and see if it will start.

Fortunatly it didn't quit on the six lane road I take into work.

In the electronics business we have found the Asian made capacitors (condenser) are short lived.

Jim